Load break disconnecting device with solid nonconducting arc suppression means



1966 H. w. MIKULECKY 3 235,696

9 LOAD BREAK DISCONNECTING DEVICE WITH SOLID NONCONDUGTING ARCSUPPRESSION MEANS Filed July 31, 1963 3 Sheets-Sheet 1 INVENTOR HARVEYw. MIKULECKY AT TORNEY Feb. 15, 1966 H. w. MIKULECKY LOAD BREAKDISCONNECTING DEVICE WITH SOLID NONCONDUCTING ARC SUPPRESSION MEANS 3Sheets-Sheet 2 Filed July 31, 1963 85 52M Luna/W2C 85 ATTORNEY Feb. 15,1966 H. w. MIKULECKY 3,235,696

LOAD BREAK DISCONNECTING DEVICE WITH SOLID NONCONDUCTING ARC SUPPRESSIONMEANS 5 Sheets-Sheet 5 Filed July 51, 1963 6 INVENTOR o HARVEYW.MIKULECKY AT TORN EY United States Patent 3,235 696 LQAD BREAKDISCONNIECTING DEVICE WITH SOLID NONCONDUCTING ARC SUPPRESSION MEANSHarvey W. Mikulecky, Racine, Wis, assignor to McGraw- Edison Company,Milwaukee, Wis, a corporation of Delaware Filed July 31, 1963, Ser. No.298,882 14 Claims. (Cl. 206-449) This invention relates to load breakdisconnecting switches which have particular, but not exclusive,application for use with housed, ground-level mounted transformersemployed with underground distribution systems.

For reasons of aesthetics as well as safety and sys tem longevity,buried electrical distribution systems are widely employed. Step downdistribution transformers employed in such distribution systems must beaccessible, however, so that they are generally mounted on aground-level concrete pad and are enclosed within a metallic housing. Itis preferable that these housings be as compact as possible, not only sothey will be inconspicuous, but also for reasons of economy and safety.As a result, conventional load break disconnecting switches and fuses,which are designed for use in installations where space is not aparticular problem, have been found unsatisfactory for use withunderground systems.

It is a primary object of the invention to provide a load breakinterrupting device which is both economical and sufficiently compactfor use within the housings of ground-level mounted transformers andwhich has sufficient interrupting capacity without being immersed in adielectric liquid.

Another object of the invention is to provide a load interrupting devicewhich may be operated with ordinary linemans tools.

Yet another object of the invention is to provide a load interruptingdevice having arc extinguishing means which moves the are off of themain current carrying contact portions prior to the interruptionthereof.

A more specific object of the invention is to provide a load breakdisconnecting device wherein nonconductive means is mounted on anelongate switch means and is resiliently urged into covering relation ofa conductive portion of the switch means relative to stationary contactmeans upon movement of the switch means away from the stationary contactmeans so that any arc struck therebetween will be extinguished. A stillmore specific object is to provide such a load break disconnectingdevice wherein the nonconductive means is a sleeve concentricallymounted on the switch means for longitudinal movement toward a coveringrelation with respect to the conductive portion. Another specific objectof the invention is to provide such a load break disconnecting devicewherein the switch means includes spring latch means for holding thenonconductive means away from the conductive portion and wherein thestationary contact means includes latch release means so that thenonconductive means is released upon movement of the switch means intoand subsequently out of engagement with the stationary contact means.

A further object of the invention is to provide a load interruptingdevice which cannot be closed until its interrupting structure isrelatched wherein no complicated interlocking linkages are required.

These and other objects and advantages of the instant invention willbecome more apparent from the detailed description thereof taken withthe accompanying drawings wherein: I

3,235,696 Patented Feb. 15, 1966 FIG. 1 shows a transformer enclosure inwhich the load break disconnecting switch according to the instantinvention is useable;

FIG. 2 schematically illustrates the transformer enclosure shown in FIG.1;

FIG. 3 is a side elevational view, with parts broken away, of one typeof load break interrupting switches according to the instant invention;

FIG. 4 is a view taken along lines 44 of FIG. 3;

FIG. 5 is a side elevational view, with parts broken away, of the deviceshown in FIG. 3 wherein the arc interrupting mechanism is shown ingreater detail;

FIG. 6 is a view taken along lines 66 of FIG. 5; and

FIG. 7 is a side elevational view, partly in section, of another type ofbreak interrupting devices according to the instant invention.

Referring now to the drawings in greater detail, FIGS. 1 and 2 show ametallic enclosure 11 for housing a ground-level transformer 11 andwhich is mounted on a concrete pad 12. The enclosure 10 is provided withan access door 13 for exposing a terminal bushing compartment 14 and aload break interrupting switch compartment 15 which are separated fromeach other by a panel 16 and from the transformer compartment by aninner panel 17. As will be understood by those skilled in the art, thevarious panels members forming the compartments 14 and 15 may becomposed of insulating material if the electrical clearance distancebetween them and electrically live parts is insufficient for thevoltages being carried.

The terminal compartment 14 is shown in FIGS. 1 and 2 to include a firstterminal 20 which is mounted on and insulated from the panel 17 by aninsulator 21 and which connects one side of the transformer secondarywinding 22 to a load conductor 24 extending downwardly through anaperture 26 in the lower end of the compartment 14 and to theunderground distribution system. The compartment 14 also includes aground terminal 25 affixed to the panel 17 for connecting the other sideof the secondary winding 22 to a ground conductor 27 extendingdownwardly through the aperture 26 to the underground system.

The compartment 15 is shown in FIGS. 1 and 2 to enclose three load breakswitches 30, 32 and 34 which are disposed in parallel side-by-siderelation. Each of the load break devices 30, 32 and 34 includes anelongate switch portion 35, 37 and 39, respectively, each of which ispivotally mounted at its lower end for movement into and out ofengagement with a stationary contact assembly 40. The stationary contactassembly 40 includes a stationary contact jaw 42, 44 and 45 for each ofthe disconnect switches 30, 32 and 34, respectively, and each is mountedon and electrically connected to a common bus support 47 which issupported on insulators 48 secured to the panel 17.

Insulating panels 50 and 52 separate the central load break switch 32,whose conductive portion 37 includes a fuse, from the outer load breakswitches 30 and 34 whose conductive portions 35 and 39, respectively,comprise switch blades. As seen in FIG. 2, one side of the transformerhigh voltage winding 55 is connected to fuse 37 and its other side isgrounded. The switch blades 35 and 39 are respectively connected toconductors 57 and 58 which are connected to a loop energizing circuitwhich is not shown but which is understood by those skilled in the artto consist of a power distribution system wherein an energy source isdisposed at each end of the system and power may flow in eitherdirection. It can be seen, therefore, from FIG. 2, that by opening theload break switch 32 the'transformer 11 may be'isolated from the loopcircuit or by opening the load break switches 30 or 34 the transformer11 may be isolated from power flow in either direction.

The switch portion 35 of disconnect switch 39, which is identical to theswitch portion 39 of disconnect switch 34, is shown in FIGS. and 6 tocomprise a hollow tubular switch blade of any suitable highly conductivematerial, such as copper. A hinge and contact member 60 is carried atthe lower end of switch blade -35and includes a pair of hinge lugs 62extending laterally its opposite sides and a pair of contact fingers 63extending from one of its ends.

A generally U-shaped hinge member 65 is provided for cooperation withthe member 60 and is afiixed by means of a bolt 66 to an insulator 68which is mounted on the panel 17 and which supports the member 65 insubstantial vertical alignment below the stationary contact assembly 42.Each of the arms of the hinge member 65 have an arcuate cam slot 76 forreceiving the hinge lugs 62 so that when the switch blade 35 is rotatedinto its closed position as shown by full lines in FIG. 3, the contactfingers 63 are forced into high pressure engagement with an invertedU-shaped resilient contact member 72 which is also secured to theinsulator 68 and which is held in high pressure engagement with a flatterminal bar '73 by the bolt 66.

The bus member 47 is shown in FIG. 3 to be generally L-shaped incross-section and to carry an elongate bumper member 76 on its edgefacing the pivotal switch blade 35. The purpose of the bumper member '76which may be composed of rubber or the like, will be explained ingreater detail hereinbelow in connection with the interrupting structureaccording to the instant invention.

As seen in FIG. 4, the stationary contact assembly 42 includes aresilient U-shaped conductive member 78 which is affixed to the bus bar47 by a bolt 79 and which provides a pair of opposed contact fingers 80,each of which has an outwardly flared end portion 82 for guiding thecontact rod 35 into its engaged position. Each of the ends 82 of thecontact fingers 80 has a longitudinal embossment 84 extending along itslength so that the contact rod 35 will snap into position against thebumper 76 upon movement toward its closed position. A U-shaped back-upspring member 85 is disposed adjacent the contact member 78 to providethe requisite contact pressure and is held in position by the bolt 79.

The arc interrupting assembly according to the instant invention iscarried adjacent the upper end of the contact rod 35 and includes anonconductive plug 90 affixed to the extreme upper end of the contactrod 35 and a nonconductive sleeve 92 which is slideably mounted in asurrounding relation on the upper portion of the contact rod 35 and isresiliently urged toward plug 90. Each of the nonconductive members 90and 92 consists of a material having good are extinguishing properties,such as Rosite 3250A and 32500, fiber, nylon, or Teflon. Anotherfavorable property exhibited by thhese materials is that they arenontracking, i.e., potentially conductive material such as carbon doesnot deposit readily on their surfaces.

More specifically, the plug 90 is slightly tapered and from its upper toits lower end its outer diameter is substantially the same as that ofthe tube 35 while its lower end 93 is of reduced diameter for insertioninto the upper end of the conductive tube 35 so that there is no sharpdiscontinuity between the surfaces of the tube 35 and the plug 90. Astop flange 94 is integrally formed at the upper end of the plug 90. Asseen in FIGS. 3 and 4, when the switch blade 35 is in its closedposition the contact fingers 80 engage the tube 35 at a pointimmediately below its juncture with the nonconducting plug 90.

In order that the disconnect switch 30 may be operated between itsconnected and disconnected positions by means of a hook stick or othersimilar tool, an eye 96 is secured to the plug 90 by means of anintegral stem 97 embedded within and completely surrounded by the plug 4so that the eye 96 is electrically insulated from the tube 35.

The nonconductive sleeve 92 is telescopically received over theconductive tube 35 and has an annular closure portion 100 extendingintegrally inward from its upper end. A cylindrical re-entrance portion102 extends back into the sleeve 92 from the inner edge of closureportion 100 and has an inner cylindrical surface 103 which closelysurrounds tube 35 to provide a bearing for the telescopic slidingengagement between thhe sleeve 92 and the tube 35. A compression spring106, which is disposed in surrounding relation to the tube 35 and withinthe member 92, ext-ends between the closure portion 100 of the tube 92and a washer 107 surrounding the tube 35 and supported against downwardmovement by a transverse pin 109 extending through the tube 35. It canbe seen therefore that the spring 106 urges the sleeve member 92upwardly of the rod 35 and toward the nonconductive plug 90 but thatthis movement is normally prevented by a latch spring 110 having agenerally U-shaped body portion 112 disposed within the tube 35 and alatch tip 114 extending radially outwardly therefrom through alongitudinal slot 115 formed adjacent the upper end of the tube 35.

When the tubular member 92 has been latched and prior to engagementbetween the conductive rod 35 and the stationary contacts 42, the sleeve92 and the latch spring 119 are in their position shown by full lines inFIG. 5. As the switch blade 35 is pivoted toward engagement with thestationary contacts 42 and as the tube 35 snaps past the embossments 84on the contact fingers 80, the bumper 76 will engage the latch tip 114of the spring 110 forcing said latch tip into the interior of the tube35. This allows the tubular member 92 to move upwardly a slight distanceuntil it engages the bumper 76 as seen by phantom lines in FIG. 5. There-entrance surface 102 thus moves over the lower edge of the latch tip114 so that upon subsequent movement of the contact rod 35 out ofengagement with the bumper 76, the latch tip 114 will be prevented fromrelatching the nonconductive sleeve 92.

When the load break switch 30 is in its closed position, current flowtherethrough is from the conductor 57 to the terminal member 73, thespring contact '72, the contact fingers 63, tubular member 35, thecontact fingers 80 and the bus bar 47.

When it is desired to interrupt load current a suitable tool is engagedwith the eye 96 and the tube 35 is rotated in a clockwise direction asviewed in FIG. 3. As the tube 35 moves out of engagement with the bumper76, sleeve member 92 will be moved upwardly by the spring 106 until itsupper closure portion engages the lower edge of the contact fingers 80as seen by phantom lines in FIG. 3. Further clockwise movement of thetube 35 will disengage its upper end from the embossed portions 84 ofthe contact fingers 80 whereupon an arc will be struck therebetween.Continued pivotal movement will then disengage the sleeve 92 from thelower edge of the contact fingers 80 whereupon it will be snappedupwardly by the spring 106 until its upper closure portion 100 engagesthe flange 94 also as shown by phantom lines in FIG. 3. As the sleeve 92moves upwardly on the tube 35, the arc existing between the contactfingers 84 and the upper end of said rod 35 will be confined to acontinually decreasing portion of the rod until it is extinguished asthe upper end of the sleeve 92 moves onto the nonconductive plug 90.This insures that the arc is forced 01f of the main contact area of therod 35 so that there is a minimum of burn damage to the main areas ofcontact of both the rod 35 and the. contact fingers 84. In additionbecause the plug 90 is. tapered from its lower to its upper end there issubstan-- tially zero tolerance between the surface 103 and the: upperend of the plug 90 so that there is no gap between these members throughwhich the arc can continue.

Resetting of the interrupting sleeve 92 is accomplished by physicallymoving said sleeve downwardly on the rod 35 until its upper closureportion 100 moves below the latch tip 114 of spring latch 110 whereuponsaid latch tip will snap outwardly through slot 115 to hold sleeve 92against movement toward plug 90 under the influence of spring 106. Itwill be appreciated that if an attempt is made to move the tube 35 intoits closed position without first resetting the interrupting sleeve 92,the latter will engage the contact fingers 80 and because its diameteris substantially greater than that of tube 35 it cannot be forcedbetween said contact fingers and accordingly movement of the switch 30into a closed position is prevented. Further, because the upper end ofthe rod 35 will be completely enclosed, prior to the latching of thesleeve 92, electrical engagement between said contact rod and thecontact fingers 80 will be impossible. Thus sleeve 92 prevents closureof the switch 30 without first resetting the same, and this isaccomplished without complicated interlocking structure.

As seen in FIG. 7, the disconnecting fuse 32 is identical with thedisconnect switch 30 except that in the fuse 32 a fuse 120 replaces thelower end of the contact tube 35. This fuse may be of any conventionalwell known type and may include, for example, a fusible element 121wound around a support rod 122 of an insulating material such as fiberglass impregnated with resin. Element 121 is electrically connected atits ends to conductive tubular member 123 and 124 respectively carriedat the upper and lower ends of the rod 122. A protective tube 125 ofinsulating material, such as fiber, is aflixed to the conductive members123 and 124 adjacent the ends of rod 122 by suitable washers 126 andcement 127.

The load break disconnecting switches just described providessimplicity, economy and a relatively high interrupting capabilitysuitable for the interrupting of load or transformer energizingcurrents. The use of the device with a ground level housed transformeris particularly advantageous because it requires a minimum of space andprovides a visible air gap for safety.

While the interrupting device according to the instant invention hasbeen shown with respect to one type of disconnecting switch or fuse andwhile it has been shown with respect to a housed transformer, it is notintended that the invention be limited thereby but only by the scope ofthe appended claims.

I claim:

1. A load break disconnecting device comprising stationary contactmeans, elongate switch means having a conductive portion and beingmounted for movement of said conductive portion into and out ofengagement with said stationary contact means, nonconductive meansmounted on said elongate switch means and movable relative thereto intoand out of covering relation of said conductive portion relative to saidstationary contact means, means resiliently urging said nonconductivemeans toward said covering relation, first means for holding saidnonconductive means out of said covering relation when said switch meansis out of engagement with said stationary contact means, second meansassociated with said stationary contact means and being operable torelease said nonconductive means from said first means and preventmovement of said nonconductive means into said covering relation whensaid conductive portion is in engagement therewith, movement of saidelongate switch means out of engagement with said stationary contactmeans being operable to release said nonconductive means for movementinto said covering relation whereby any are struck between saidstationary contact means and said conductive portion will beextinguished.

2. A load break disconnecting device comprising stationary contactmeans, elongate switch means having a conductive portion and beingmounted for movement of said conductive portion into and out ofengagement with said stationary contact means, nonconductive meansmounted on said elongate switch means for movement into and out ofcovering relation of said conductive portion relative to said stationarycontact means, means resiliently urging said nonconductive means towardsaid covering relation, means for holding said nonconductive means awayfrom said conductive portion, and release means actuable when saidelongate switch means is moved into its closed position to release saidnonconductive means toward said covering relation and into engagementwith said stationary contact means, movement of said switch means out ofengagement with said stationary contact means being operable to releasesaid nonconductive means for movement into said covering relationwhereby any are struck between said stationary contact means and saidportion will be extinguished.

3. A load break disconnecting device comprising stationary contactmeans, elongate switch means having a conductive portion and beingpivotally mounted at one end for movement of said conductive portioninto and out of engagement with said stationary contact means,nonconductive means mounted on said elongate switch means for movementinto and out of surrounding relation to said conductive portion, meansresiliently urging said nonconductive means toward said conductiveportion, latch means for holding said nonconductive means awa from saidconductive portion, and latch release means actuable when said elongateswitch means is moved into its closed position to release said latch andallow said resilient means to urge said nonconductive means toward saidconductive portion and into engagement with said stationary contactmeans, movement of said switch means out of engagement with saidstationary contact means being operable to release said nonconductivemeans for movement onto said conductive portion whereby any are struckbetween said stationary contact means and said portion will beextinguished.

4. A disconnecting device comprising first and second spaced apartterminal means, stationary contact means mounted on one of said terminalmeans, elongate switch means having a conductive portion adjacent oneend thereof and being mounted at its other end on the other of saidterminal means for movement of said conductive portion into and out ofengagement with said stationary contact means, sleeve means disposed insurrounding relation to a portion of said elongate conductive means andbeing composed of a nonconductive material, means resiliently urgingsaid nonconductive sleeve means toward the one end of said switch meansto cover the conductive portion thereof, latch means for holding saidnonconductive sleeve means away from said conductive portion, and latchrelease means actuable when said elongate switch means is moved into itsclosed position to release said latch and allow said resilient means tourge said nonconductive sleeve means toward said nonconductive portionand into engagement with said stationary contact means, movement of saidswitch means out of engage ment with said stationary contact means beingoperable to release said nonconductive sleeve means for movement ontosaid conductive portion whereby any are struck between said stationarycontact means and said conductive portion will be extinguished.

s. A disconnecting device comprising first and second spaced apartterminal means, stationary contact means mounted on one of said terminalmeans, elongate switch means having a conductive portion and beingpivotally mounted at one end on the other of said terminal means formovement of said conductive portion into and out of engagement with saidstationary contact means, said switch means also including anonconductive portion adjacent the free end thereof, nonconductivesleeve means disposed in surrounding relation to a portion of saidelongate switch means, means resiliently urging said nonconductivesleeve means toward said nonconductive portion to cover the conductiveportion of said switch means,

latch means for holding said nonconductive sleeve means away from saidnonconductive portion, and latch release meansmounted on said oneterminal means and engageable with said latch means to release saidlatch and allow said resilient means to urge said nonconductive sleevemeans toward said nonconductive portion and into engagement with saidstationary contact means when said elongate switch means is moved intoits closed position, movement of said conductive portion out ofengagement with said stationary contact means being operable to releasesaid nonconductive sleeve means for movement onto said conductiveportion whereby any arc struck between said stationary contact means andsaid conductive portion will be extinguished.

6. A load break disconnecting device comprising first and second spacedapart terminal means, a pair of pposed contact fingers mounted on one ofsaid terminal means, elongate switch means having a conductive portionadjacent one end and being pivotally mounted adjacent its other end onthe other of said terminal means for movement of said conductive portioninto and out of engagement between said contact fingers, said conductiveportion being electrically connected to said other terminal,nonconductive sleeve means disposed in surrounding relation to asubstantial portion of said elongate switch means and being mounted forsliding movement longitudinally therealong, spring means disposed withinsaid sleeve means for resiliently urging said sleeve means toward saidconductive portion, said switch means having an aperture formed thereinadjacent said conductive portion, spring latch means disposed withinsaid switch means and having a latch tip extending through said apertureto prevent movement of said sleeve means toward said conductive portion,bumper means mounted on said one terminal means and engageable with saidlatch tip when said elongate switch means is moved into its closedposition to force the latter into said switch means and release saidsleeve means for movement toward said conductive portion and intoengagement with said contact fingers, movement of said conductiveportion out of engagement with said contact fingers being operable torelease said nonconductive sleeve means for movement onto saidconductive portion whereby any are struck between said stationarycontact means and said conductive portion will be extinguished, thewidth of said sleeve means being substantially greater than that of saidconductive portion so that engagement of said switch means between saidcontact fingers is prevented until said sleeve means has been relatched.

7. A load break disconnecting device comprising stationary contactmeans, elongate switch means having a conductive portion adjacent oneend and being pivotally mounted adjacent its other end for movement ofsaid conductive portion into and out of engagement with said stationarycontact means, nonconductive sleeve means disposed in surroundingrelation to a substantial portion of said elongate switch means andbeing mounted for sliding movement longitudinally therealong, springmeans for resiliently urging said sleeve means toward said conductiveportion, said switch means having an aperture formed therein adjacentsaid conductive portion, spring latch means disposed within said switchmeans and having a latch tip extending through said aperture to preventmovement of said sleeve means toward said conductive portion, latchrelease means mounted adjacent said stationary contact means andoperable when said elongate switch means is moved into its closedposition to force said latch tip into said switch means and release saidsleeve means for movement toward said conductive portion and intoengagement with said stationary contact means, movement of saidconductive portion out of engagement with said stationary contact meansbeing operable to release said nonconductive sleeve means for movementonto said conductive portion whereby any are struck between saidstationary contact means and said 8 conductive portion will beextinguished, the width of said sleeve means being substantially greaterthan that of said conductive portion so that engagement of said switchmeans and said stationary contact means is prevented until said sleevemeans has been relatched.

8. A load break disconnecting device comprising first and second spacedapart terminal means, a pair of opposed contact fingers mounted on oneof said terminal means, elongate switch means having a conductive portion adjacent one end and being pivotally mounted adjacent its other endon the other of said terminal means for movement of said conductiveportion into and out of engagement between said contact fingers, saidconductive portion being electrically connected to said other termi'nal, said switch means also including a nonconductive portion adjacentthe free end thereof, nonconductive sleeve means disposed in surroundingrelation to a substantial portion of said elongate conductive means andbeing mounted for sliding movement longitudinally therealong, springmeans disposed within said sleeve means for resiliently urging saidsleeve means toward said nonconductive portion to cover the conductiveportion of said switch means, said switch means having an apertureformed therein adjacent said conductive portion, spring latch meansdisposed within said switch means and having a latch tip extendingthrough said aperture to prevent movement of said sleeve means towardsaid nonconductive portion, bumper means mounted on said one terminalmeans and engageable with said latch tip when said elon gate switchmeans is moved into its closed position to force the latter into saidswitch means and release said sleeve means for movement toward saidnonconductive portion and into engagement with said contact fingers,embossment means formed on each of said contact fingers so that saidlatch tip will be moved into positive engagement with said bumper means,movement of said conductive portion out of engagement with said contactfingers being operable to release said nonconductive sleeve means formovement onto said conductive and nonconductive por tions whereby anyare struck between said stationary contact means and said conductiveportion will be extin guished, the width of said sleeve means beingsubstantially greater than that of said conductive portion so that engagement of said switch means between said contact fingers is preventeduntil said sleeve means has been re latched.

9. The load break disconnecting device set forth in claim 8 wherein saidelongate switch means comprises a switch blade.

10. The load break disconnecting device set forth in claim 8 whereinsaid elongate switch means includes an elongate fuse and wherein saidconductive portion thereof comprises a rod-like member extending axiallyfrom said fuse and being electrically connected thereto.

11. A disconnecting device comprising first and second spaced apartterminal means, stationary contact means mounted on one of said terminalmeans, elongate switch means having a substantially cylindricalconductive portion and being pivotally mounted at one end on the otherof said terminal means for movement of said conductive portion into andout of engagement with said stationary contact means, said switch meansalso including a plug portion disposed adjacent the conductive portionand being tapered outwardly therefrom, sleeve means having a centralopening disposed in concentric surrounding relation to said elongateswitch means, said sleeve means and the plug portion of said switchmeans being a nonconductive nontracking material, resilient means urgingsaid sleeve means toward said plug portion to cover the conductiveportion of said switch means, latch means for holding said sleeve meansaway from said plug portion, and latch release means mounted on said oneterminal means and engageable with said latch means to release saidlatch means and allow said resilient means to urge said sleeve meanstoward said plug portion and into engagement with said stationarycontact means when said elongate switch means is moved into its closedposition, movement of said conductive portion out of engagement withsaid stationary contact means being operable to release said sleevemeans for movement onto said plug portion whereby any are struck betwensaid stationary contact means and said conductive portion will beextinguished, the diameter of the opening in said sleeve means beingsubstantially equal to that of the plug portion at the largest pointthereof so that there is a minimum clearance therebetween forcontinuation of said arc.

12. A load break disconnecting device comprising first contact means,second contact means having a conductive portion and being mounted formovement of said conductive portion into and out of engagement with saidfirst contact means, nonconductive means mounted on said second contactmeans for movement relative thereto into and out of covering relation ofsaid conductive portion relative to said first contact means, meansresiliently urging said nonconductive means toward said coveringrelation, means for holding said nonconductive means away from saidconductive portion when said second contact means is out of engagementwith said first contact means, said first contact means including meansengageable by said nonconductive means when said second contact means isin engagement with said first contact means, and means actuable whensaid second contact means is moved into its closed position to releasesaid nonconductive means towards said covering relation and intoengagement with said first contact means, movement of said secondcontact means out of engagement with said first contact means beingoperable to release nonconductive means for movement into said coveringrelation whereby any are struck between said first contact means andsaid conductive portion will be extinguished.

13. A disconnecting device including contact means, elongate switchmeans having a conductive portion and being mounted for movement of saidconductive portion into and out of engagement with said contact means,nonconductive means disposed in surrounding relation to at least aportion of said elongate switch means, means resiliently urging saidnonconductive means toward said conductive portion, latch means forholding said nonconductive means away from said conductive portion whensaid conductive portion is out of engagement with said contact means,said contact means including means engageable by said nonconductivemeans when said conductive portion is in engagement with said contactmeans and release means actuable when said conductive portion is movedinto engagement with said contact means to release said latch means andallow said resilient means to urge said nonconductive means toward saidconductive portion and into engagement with said contact means, movementof said switch means out of engagement with said contact means beingoperable to release said nonconductive from movement onto saidconductive portion whereby any are struck between said contact means andsaid conductive portion will be extinguished.

14. A load break disconnecting device including contact means, elongateswitch means having a conductive portion and being mounted for movementof said conductive portion into and out of engagement with said contactmeans, nonconductive means disposed in surrounding relation tosubstantial portion of said elongate switch means and being mounted forsliding movement longitudinally therealong, spring means disposed withinsaid nonconductive means for resiliently urging the latter toward saidconductive portion, said switch means having an aperture formed thereinadjacent said conductive portion, spring latch means disposed withinsaid switch means and having a latch tip extending through said apertureto prevent movement of said nonconductive means toward said conductiveportion, trip means associated with said contact means and engageablewith said latch tip when said conductive portion is moved intoengagement with said contact means to release said nonconductive meansfor movement toward said conductive portion and into engagement withsaid contact means, movement of said conductive portion out ofengagement with said contact means being operable to release saidnonconductive means for movement onto said conductive portion wherebyany arc struck between said contact means and said conductive portionwill be extinguished.

References Cited by the Examiner UNITED STATES PATENTS 1,833,173 11/1931Murray 200-151 References Cited by the Applicant UNITED STATES PATENTS649,554 5/1900 Schwedtmann. 2,262,386 11/1941 Crabbs.

2,277,422 3/ 1942 Walle. 2,294,801 9/ 1942 Rawlins. 2,591,950 4/1952Lindell.

FOREIGN PATENTS 604,498 9/1960 Canada.

KATHLEEN H. CLAFFY, Primary Examiner.

ROBERT S. MACON, Examiner.

2. A LOAD BREAK DISCONNECTING DEVICE COMPRISING STATIONARY CONTACTMEANS, ELONGATE SWITCH MEANS HAVING A CONDUCTIVE PORTION AND BEINGMOUNTED FOR MOVEMENT OF SAID CONDUCTIVE PORTIONINTO AND OUT OFENGAGEMENT WITH SAID STATIONARY CONTACT MEANS, NONCONDUCTIVE MEANSMOUNTED ON SAID ELONGATE SWITCH MEANS FOR MOVEMENT INTO AND OUT OFCOVERING RELATION OF SAID CONDUCTIVE PORTION RELATIVE TO SAID STATIONARYCONTACT MEANS, MEANS RESILIENTLY URGING SAID NONCONDUCTIVE MEANS TOWARDSAID COVERING RELATION, MEANS FOR HOLDING SAID NONCONDUCTIVE MEANS AWAYFROM SAID CONDUCTIVE PORTION, ASND RELEASE MEANS ACTUABLE WHEN SAIDELONGATE SWITCH MEANS IS MOVED INTO ITS CLOSED POSITION TO RELEASE SAIDNONCONDUCTIVE MEANS TOWARD SAID COVERING RELATION AND INTO ENGAGEMENTWITH SAID STATIONARY CONTACT MEANS, MOVEMENT OF SAID SWITCH MEANS OUT OFENGAGEMENT WITH SAID STATIONARY CONTACT MEANS BEING OPERABLE TO RELEASESAID NONCONDUCTIVE MEANS FOR MOVEMENT INTO SAID COVERING RELATIONWHEREBY ANY ARC STRUCK BETWEEN SAID STATIONARY CONTACT MEANS AND SAIDPORTION WILL BE EXTINGUISHED.